Vibrating screen



May 5, 1959 L. H. LEHMAN 2,884,790 VIBRATING SCREEN Filed Sept. 24. 1954 2 Sheets-SheetI 1 Lewls H. LEHMAN BY ATTORNEY May5, 1959 l LH. LEHMAN 2,884,790

VIBRATING SCREEN Filed sept. 24. 1954v 2 sheets-smet 2 INVENToR. Lewis H. LEHMAN 7707?/VEY United States Patent() VIBRATING SCREEN Lewis H.` Lehman, Chicago, Ill., assignor to Productivev Equipment Company, Chicago, Ill., a corporation of Illinois Application September 24, 1954Serial`No. 458,156

4` Claims. (Cl. 74-61).

This* invention relates to improvements in vibratingi screens. More particularly, thisy invention relates-to iinprovements in screens thatr are vibrated at high speeds.

It is therefore an objectof the' present invention toprovide an improved screen that can bevibrated` at high speed;

In the separating and` sizing of products, it is desirable that those products be subjected tov rapid vibrations'of rela'- tively small amplitude. In recognition of this fact,-` a number' of high speed vibrating screensv have been proposed; and some of them-have been used. One screen-,that has been used effectively and widely isl disclosed by Lewis E. Solden Patent No. 2,267,143 which issued December 23, 1941. The screensY made in accordance withY that patent have given excellent service and havebeen well received. The vibrating screen provided bythev present'inventionretains'allof the desirable structural features of thevibrating screen of; the said patent but additionally provides'further desirable structural features.

In the operation of high speed vibrating screens, the partsv of the screen are subjected to rapidr and repeated changes of movement. Where those parts are sizable, the momentum created in themy tends to resist the ehangesiofdirection of movement. This momentumV can apply size able shearing forces to the parts of the vibrating screens andy those shearing forces can eventually fatigue some of the parts. This, of course, is objectionable. The present invention minimizes the shearing forces applied to certain parts of vibrating'screens by'providi'ng a sizeablelbearng surface between the vibration-generatingv portion of'A the device andV the vibratable portion `of' the device. This large bearing surface can readilywithstand the shearing forces. and will minimize the shearing forces applied-` to otherpa'rts ofV the1 vibrating; screen. It is'therefore an" object of the present invention to provide a vibratingescreen with a large 4bearing surface between the vibration-gen'- erating portion of the device and the vibratable portion ofi the device.

It is desirable in a high speed vibrating'screen tohave a shaft that is concentric'throughout its length and' which can be assembled with, and disassembled from, the other parts rof that screen. Such a shaftis'inexpensive to manufacture and is readily handled in fabricating'the machine. The present invention provides such a shaft and' thereby attains: economical and ready fabrication ofthe vibrating screen.

The shaft of the vibrating screen providedl by the# present' invention has a central portion with two outwardly extending portions of reduced diameter. These portions of'reduced diameter coact'with the center portion to-provide shoulders that can receive andl positively position radially-directed discs. These discsare thenA locked in po- -sition on the shaft by suitable securing elements suchas nuts. In addition, the shaft has a pulley-receiving portion that extends outwardly beyond one of they sections of reduced diameter, and that section receives a pulley. This pulley is held in position by a suitable fastener such as a nut. The pulley can be installed or removed without af ICC fecting the radially-extending discs on the shaft. Hence, the shaft can be left undisturbed even though the pulley must be removed for inspection or replacement.

I Other and further objects and advantages of the present invention should become apparent from an examination ofthe drawing and accompanying description.

In the drawing and accompanying description two preferred embodiments of the present invention are shown and described but it is to be understood that the drawing and accompanying description are for the purpose of illustration only and` do not limit the invention and that the invention will be defined by the appended claims.

In the drawing- Fig. 1 is a broken sectional view through one form of the screening device provided by the present invention,

Fig, 2 is an end view of one of the bearing-supporting rings used in the screen of Fig. l,

Fig. 3 is a sectional view of a portionk of the screen of Fig. l, and it is taken along the plane indicated by the line 3 3 in Fig. l, and Fig. 4 is a cross sectional View through a portion of another form ofvibrating screen made in accordance with the principles and teachings of the present invention.

Referring to the drawing in detail, the numeral 12 denotesthe side walls of a vibrating screen that is made in accordance with the principles and teachings of the present invention. Two such. side walls arev provided for that screen, and each side is reinforcedv by a generally square metal plate 10. The plates 10` are mounted at the exterior faces of the side walls 12', and they stitfen thoseside walls; The side walls 12 and the reinforcing plates 1`0 will be suitably held in positive and intimate face-to-face relation by'bolts, such as the bolts 26.` When so held, those plates tend to become, and can be considered to be, integral parts of 'theside Walls of the frame of the vibrating screen.

Openings 14 are provided in the side walls ofthe screen; and those openings will preferably be circular in contiguration. The openings 14 will be in register with each other and they will receive annular flanges 18 on bearing-supporting rings 16. These `bearing-supporting rings will preferably be formed as castings, and they will have radiallyextending anges 20 in addition to the annular flanges 18. Furthermore, they will have cylindrical recesses 22, and will have threaded sections 24. The annular anges 18 on the bearingesupporting rings 16' will lit snugly within the openings 14 in thev side walls 'of the, frame of the screen. In doing so, the iianges 18 constitute large bearing surfaces on those rings to receive the side walls. The reinforcing'plates 10 coact with the side walls 12 to pro'- vide a wide bearing area that can distribute the forces 1 transmitted by the annular flanges 18; and thus lthe forces applied to the plates 10 and the side walls 12 are well within the strength limitations of those members. Consequently, the large bearing area, provided bythe annular lianges 18 and the plates 10 and walls 12, can absorb the greatest part of the shearing forces generated in the screen and will relieve other parts of the screen of the full brunt of those forces.

` The bolts 26 extend through enlarged vopenings 27S in the side walls of the trarne of the screen and seat in threaded openings 29 in the bearing-supporting rings 16.

forces will be well within the strength limitations of those bolts. The enlarged openings 27 will not only relieve the bolts 26 of shearing forces, but they will also facilitate rapid assembly of the bearing-supporting rings 16 with the side walls of the frame of the screen.

Antifriction bearings 28 are mounted with their inner races supported on the outer ends of the bearing-supporting rings 16. The inner races of the bearings 28 will telescope over the threaded portions 24 of the bearingsupporting rings 16 and will be locked in position on those bearing-supporting rings by nuts 30. Those nuts thread onto and will be held by the threads of the threaded sections 24.

The outer races of the antifriction bearings 28 extend within and snugly tit recesses in radially-directed discs 32. Each of the discs 32 has a weight 34 releasably secured to it by bolts 36. -A pair of radially-directed discs 38 are mounted adjacent the radially-directed discs 32. Each of the discs 38 has an opening to receive a bolt 42; and the 'bolts 42 hold weights 40 in assembled relation with the discs 38. The weights 34 and 40 are generally comparable, and they serve as counterweights for the screen.

The discs 32 and 38 have a number of axially-directed openings, not shown, formed in them; and those openings are circumferentially spaced apart. Those openings make it possible -for the two discs to be adjusted circumferentially of each other and still have at least one opening in each disc in register with a corresponding opening in the other disc; and the registered openings can receive a bolt to lock the two discs together for 'conjoint rotation.

The discs 38 have cylindrical openings 45 therethrough, and those openings are smaller than tihe inner diameters of the inner races of the bearings 28. Moreover, those openings are spaced outwardly of the bearings 28.

The portions of the discs 32 which receive the outer races of the bearings 28 will be concentric with the bearing-supporting rings 16. However, interacting surfaces 43 are provided between the disc 32 and 38, and those surfaces are eccentric to the bearing-supporting rings 16 and to the recesses in the discs 32 that receive the outer races of the bearings 28. Furthermore, the inter-acting surfaces 43 between the discs 32 'and 38 are eccentric to the cylindrical openings 45 in the discs 38. The inter-acting surfaces 43 are circular or cylindrical, and they permit rotation of the discs 32 and 38 relative to each other. The rotation of those discs about the inter-acting surfaces 43 can establish an eccentricity Vof variable degree between the recesses lof the discs 32 and the cylindrical openings 45 of the discs 38. The extent of eccentricity is regulated by the above-described relative rotation of the discs 32 and 38.

The numeral 44 denotes an elongated shaft which is concentric throughout its length. The center portion of the shaft is of a diameter smaller than the inner diameter of the bearing-supporting rings 16. The shaft 44 has outer portions 46 of even smaller diameter, and those outer portions coact with the center portion of the shaft 44 to dene radially-directed shoulders. The shaft 44 has threaded portions 48 which are disposed axially outwardly of the outer portions 46 and the left hand end of the shaft 44 has a pulley-receiving portion disposed axial- 50 to hold the discs 38 in `assembled relation with the shaft 44.

The inner races of the anti-friction bearings 28 will be stationary and will be locked to the bearing-supporting rings 16. The outer races of the anti-friction bearings 28 will rotate about the horizontal axis of the shaft 44 Iand will support that shaft through the medium of the discs 32 and 38.

A pulley 56 is releasably securable to the pulley-receiving portion 54 of the shaft 44. A key 58 extends partially into the pulley 56 and partially into the pulley-receiving portion 54 of the shaft 44. A nut 62 is threaded onto the threads of the threaded section 60 to coact with rtihe key 58 to secure the pulley 56 to the shaft 44. The recesses 22 in the bearing-supporting rings 16 receive annular supports 64. Bolts 66 extend through openings in the supports 64 and seat in the bearing-supporting rings 16. These vbolts will maintain the supports 64 in assembled relation with the bearing-supporting rings 16. Those rings, in turn will 'be held in assembled relation with the walls of the frame of the vibrating screen by the bolts 26. The annular supports 64 receive the opposite ends of a connecting tube 68 Which telescopes over the shaft 44. The endsof the tube 68 are suitably secured to the annular supports 64, as by welding. The bolts 66 thus secure the tube 68 to each of the bearing-supporting rings 16, and thereby secure that tube to the side walls of the frame of the vibrating screen. The tube 68 will stiifen the vibrating screen and will connect the side walls of the screen together and hold them against twisting. In this way, the tube 68 maintains the opposite sides of the vibrating screen in register with each other.

Elongated angles 70 lare secured at opposite sides of the frame and those angles are disposed below elongated securing plates 72. The lower ends of the securing plates extend into reentrant edges of a perforated plate or woven 74. Suitable fasteners, of the type shown in Fig. 4, will be'provided to pull the securing plates 72 toward the side Walls of the frame of the screen. This movement of the elongated securing plates 72 will tension the perforated plate or woven screen 74.

A guard 78 of generally standard design is provided to enclose the rotating parts supported at the right hand end of the shaft 44. A guard 80 of generally `standard design is provided to enclose most of the rotating parts disposed at the lefthand end of the shaft 44. That guard does not enclose the pulley 56 which must extend out beyond the guard to receive a belt that will be driven by ly outwardly beyond the threaded portion 48. The porshaft 44. Keys 52 are provided which extend partly into the discs 38 and partly into the reduced diameter portions 46 of the shaft 44. Those keys will coact with the nuts a suitable source of power, such as a motor.

In assembling the device provided by the present invention, the Walls 12 and the reinforcing plates 10 are placed in register with each other. Thereafter, the bearing-snpporting rings 16 are telescoped toward each other so the circular anges 18 thereof extend into and are held by the openings 14 in the side walls of the frame. The tube 68 is suitably secured to the annular supports 64, and those supports are then bolted into the recesses 22 of the bearing-supporting rings. Once this has been done, the'side walls of the frame are secured together through the medium of the tube 68. Thereafter, the inner races of the anti-friction bearings 28 are telescoped into position and are locked thereby the nuts 30. The discs 32 will have lbeen pressed upon the outer races of the antifriction bearings 28, and the discs 38 will lbe placed in engagement with the discs 32. The interacting surfaces 43 between those discs will permit ready assembly of those discs while yet permitting relative rotation of those discs. The bolts, described above, will be used to lock the discs- 32 and 38 together and to prevent accidental relative rotationof those discs. The shaft 44 will be mounted in the tube I68 prior to the movement of the ydiscs 38 in to engagement with the discs 32, and those discswill have the openings 45 thereof telescoped over the reduced diameter portions 46 as those discs are moved into engagement with the discs 32. Once the discs 38 assa'zao have been moved into engagementwiththe shoulders on the/shaft 44 the nuts 48 will` be tightened to lock those discsagainst separation from `the shaft .4.4. The pulley 5.6 willl finally be mounted on the pulley-receivingv portion 54.

Once the vibrating screen has been assembled, the pul- 'ley 56 can be rota-ted, as by connecting it to a motor through a Vebelt, and thereafter the operation of the vibrating screen will becomparable Vto the operation of thetvibratingscreen of the said patent. The eccentricity established between the recesses of the discs 32 and the openings v45 of the discs 3.8 will establish the desired eccentricity between. the shaft 44 and the bearing-support ingrings `16; and the latter eccentricity will force the side walls 12 of the vibrating screen to vibrate as the shaftv 44 rrotates.concentrically about its aXis yat high speed.

.Fig 4 shows another form of vibrating screen that is made in accordance with the principles andA teachings of the present invention, andthe side walls 84 `of that screen are `provided with generally square reinforcing plates 82. Openings 86 are provided in the side walls 84 and the plates--82 `of the frame of that screen, and those openings are in register withv each other. lBearing-supporting rings 88 areprovided with annular anges 90, and those flanges extend# snugly within the openings 86 in the side walls and plates of the frame of that screen. Those circular lianges provide large ibearing areas Vthatcan absorb most ofthe shearing `forces generated in the vibrating screen. Each of the bearing-supporting rings `88v has a recess 92 atf'its inner face.

Bolts 94 extend through enlarged openings 96 in the side walls of the frame of the screenof Fig. 4, and those bolts seat in openings inv the bearing-supporting rings 88. TheI enlarged openings relieve the bolts 94 of shearing forces and they also facilitate rapid and easy fabrication and assembly of the vibrating screen. Anti-friction bearings 98 are mounted on the bearingsupporting rings 88, and nuts 100 are threaded onto threaded portions of those bearing-supporting rings. The nuts bear against the inner races of the anti-friction bearings and lock them against rotation relative to the bearings-supporting rings 88.

The outer races of the bearings 98 support radiallyextendingjdiscs 102. Each of the discs 102 has an openinto receive a bolt 106. The =bolts 106 will secure Weights 104 to the discs 102. Radial-ly-extending discs 108 areA provided adjacent the discs 102. Each of the discs 108 has an opening that can receive the bolt 112, and thatlboltrsecures a weight 110 to that disc. Inter-acting surfaces 114 are provided between the discs 102y and 108, and those surfaces are eccentrically disposed. A `number of angularly spaced openings, not shown, are provided in the discs 102 and 108; and those openings can receive bolts that will hold those discs in any one of a nuzmlber of relatively rotated positions. The discs 102 and 108 are closely comparable to the discs 32 and 38 of Fig. l. The principal difference lbetween the discs 108 and the discs 38 is that the discs 108 have the inner races of antifriction bearings 116 mounted on them.

` The discs 108 have :cylindrical openings therethrough which receive reduced diameter portions 120 of the elongated shaft 1=18. The reduced diameter portions 120 of the shaft 118 coaet with the center portion of that shaft to define radially-directed shoulders. The discs 108 Will bear against those shoulders and will be held in tight engagement with them by the `nuts 124 which are threaded onto the threaded portions 122 of the shaft 118. Washers 123 are disposed between the nuts 122 and the inner races of the vanti-friction bearings 116. Those washers transmit force from the nuts 122 to the inner raices of the `bearing 116 and thence to the discs 108; and in this way the discs 108 are held solidly against the shoulders on the shaft 118.

f' The shaft 118 has a pulley-receiving `portion 126 at one end thereof, and that portion of the shaft1`t18 will receive a pulley 128. A threaded portion of` the shaft 118 will receive a nut 130, and that nut willV hold the pulley 128. in position on the shaft 118.

A guard 132 is provided to enclose most of the rotating elements disposed at the left hand end of` the shaft 118. However, that guard does not enclose the pulley 128 which must be disposed outwardly of that guard to receive a belt that will .be connected to a suitable source of power. The guard 132 is supported within a frame 134, and that frame will be spaced from the oor or other support -by a resilient sleeve 136. .This sleeve will be of standard design and will cushion the forces which` the vibrating screen might otherwise transmit to the floor or othersupport.

The recesses in` the bearing-supporting rings 88 receive annular supports 138. These annular supports will be held within the recesses 90 by bolts 140. The outer ends of a tube 142 will extendV within the annular supports 138 and will be secured to them, as by welding;

An angle 144 is secured to each of the side walls of the screen provided` by the present invention, 'and those angles will be disposed below securing elements 146. These securing elements will be releasably drawn toward the side walls of the screen by fasteners 148. Those fasteners will preferably be headed bolts that are equipped with wing nuts. The lower ends of the securing elements 146 will engage reentrant edges` of a perforated screen or plate 150. Tightening, of the fasteners 148 will cause tensioning of the screen or plate 150.

The screen of Fig. 4 is also provided with elongated angles 152, with elongated securing elements 154 with fasteners 156 and with a perforated screen or plate 158. The angles 152 will underlie the elongated secu-ring elements 154 and those elements will` be selectively drawn toward the side walls of the screen by the fasteners 156. The lower ends of the securing elements 154 will extend into the reentrant edges of. the perforated screen. or plate 158.

The operation of the vibrating screen shown in Fig. 4 is largely similar to the operation of the vibrating screen shown in Fig. `l. However, the vibrating screen of Fig. 4 has two sets of anti-friction bearingsl and itis supported by the external frame 134 rather than being carried by the side walls of the screen itself, as is the case of the vibrating device of Fig. 11.

In both forms of the invention the shaft is simple and straight-forward and `minimizes the cost and the time of fabrication of the device. In addition, the bearing surface provided bythe circular flanges protect the rest of the vibrating screens from. most of the shearing forces generated by those screens.

Whereas two preferred forms of the present invention have been shown and described in the drawing and accompanying description, it should be apparent to those skilled in the art that various changes may be `madein the form of the invention without affecting the scope thereof.

What I claim is:

1. A high speed vibrating device that comprises a frame with two spaced-apart side walls, openings 4in said side walls, a tubular member that is disposed lbetween said side Walls of said frame and has the ends thereof extending through and projecting beyond said openings in said side walls, bearing-supporting rings that are disposed outwardly of said side walls of said frame and have recesses that are in register with and telescope over and are held tixedly spaced apart by said tubular member, said bearing-supporting rings being rigidly secured to said side walls of said frame and having shoulders thereon, anti-friction bearings mounted' on said bearing-supporting rings and having the inner races thereof abutting and fixedly secured to said shoulders of said bearing-supporting rings, radially-directed discs secured to and rotatable with the outer races of said anti-friction bearings, a secondl set of radially-directed discs that'is disposed axially outwardly of the first said set of discs, interacting circular surfaces on the first said Iand said second sets of ldiscs that permit adjusting rotation of said second set of discs relative to the rst said set of discs, said interacting surfaces being eccentric of said bearing-supporting rings, each of saidsecond set of discs having a cylindrical opening therethrough, said openings being eccentric of said interacting surfaces, an elongated cylindrical shaft that has the center thereof disposed within said tubular member and has the ends thereof projecting outwardly beyond said tubular member and beyond said bearing-supporting rings and through and beyond said cylindrical openings in said secondset of discs, those portions of said shaft that project outwardly beyond said tubular member and beyond said bearing-supporting rings being cylindrical and of reduced diameter and being concentric with said center of said shaft, said outwardly projecting reduced diameter portions of said shaft coacting with said center of said shaft to define radially-directed shoulders adjacent the opposite ends of said shaft, said reduced diameter cylindrical portions receiving the hub portions of said second set of discs, said shoulders receiving and limiting movement of said second set of discs toward each other, said shaft having threaded sections disposed axially outwardly of said reduced diameter sections thereof and being spaced from said radially-directed shoulders distances less than the thicknesses of said hub portions of said second set of discs, and nuts that telescope over said threaded sections and force said second set of discs against said shoulders, said shaft having a pulley-receiving portion disposed outwardly of the threaded portion at one end of said shaft, said tubular member, said bearing-supporting rings and the shoulders thereon, and said shaft and the shoulders thereon precisely positioning said discs, whereby said bearings are substantially free of side thrust.

2. A high speed vibrating device that comprises a frame with two spaced-apart side walls, a tubular member that is disposed between. said side walls of said frame and has the ends thereof extending through and projecting beyond openingsfin said side walls, bearing-supporting rings that are disposed outwardly of said side walls of said frame and are in register with said tubular member, said bearing-supporting rings havingconfronting faces and having recesses that extend inwardly from said faces, said bearing supporting rings being rigidlysecured to said side @11s of said frame, annular supports that are mounted on said tubular member at the opposite ends thereof and that telescope into recesses, the outer peripheries of said annular supports engaging the inner peripheries of said recesses and coacting with said inner peripheries of said recesses to transmit and receive forces, the inner peripheries of said annular supports engaging the outer periphery of said tubular member and coacting with said outer periphery of said tubular member to transmit and receive forces, anti-friction bearings mounted on said lbearing-supporting rings and having the inner races thereof iixedly secured to said bearing-supporting rings, radially-directed discs secured to and rotatable Iwith the outer races of said anti-friction bearings, a second set of radially-directed discs that is disposed axially outwardly of the rst said set of discs, interacting circular surfaces on the first said and said second sets of discs that permit adjusting rotation of said second set of discs relative to the first set of discs, said interacting surfaces being eccentric of said bearing-supporting rings, each of said second set of discs having a cylindrical opening therethrough, said openings being eccentric of said interacting surfaces, an elongated cylindrical shaft that has the center thereof disposed 'within said tubular member and has the ends thereof projecting outwardly beyond said tubular member and beyond said bearing-supporting rings and through and beyond said cylindrical openings in said second set of discs, said ends of said shaft having cylindrical sections of reduced diameter that coact with said center of said shaft to define radially-directed shoulders, said shoulders receivingand holding limiting movement of said second set of discs toward each other, said shaft having threaded sections disposed axially outwardly of said reduced diameter sections thereof, and nuts that telescope over said threaded sections and force said second set of discs against said shoulders, said shaft having a pulley-receiving portion disposed outwardly of the threaded portion at one end of said shaft, said shaft being concentric throughout its length, said shaft being movable radially of said tubular member during the rotation of said shaft, the amount of radial movement of said shaft relative to said tubular member being determined by the setting of said interacting circular surfaces on the first said and said second sets of discs.

3. A high speed vibrating device that comprises a frame with two spaced-apart side walls, a tubular member that is disposed between said side 'walls of said frame, openings in said side walls of said frame that are in register with each other, bearing-supporting rings that are disposed outwardly of said side walls of said frame and are in register with and telescope over the ends of said tubular member, said bearing-supporting rings having projections thereon that extend into and snugly t said openings in said side walls of said frame and also having radially extending flanges that are coextensive with those portions of said side walls that encircle and extend outwardly from said annular projections, and fasteners that extend through openings in said side walls and are held by said radially extending flanges of said bearing-supporting rings, anti-friction bearings mounted on said `bearing-supporting rings and having the inner races thereof iixedly secured to said bearing-supporting rings, radially-directed discs secured to and rotatable with the outer races of said antifriction bearings, said flanges extending radially outwardly beyond said outer races, a second set of radially-directed discs that is disposed axially outwardly of the first said set of discs, interacting circular surfaces on the first said and said second sets of discs that permit adjusting rotation of said second set of discs relative to the rst said set of discs, said interacting surfaces being eccentric of said bearing-supporting rings, each of said second set of discs having a cylindrical opening therethrough, said openings being eccentric of said interacting surfaces, an elongated cylindrical shaft that has the center thereof disposed within said tubular member and has the ends thereof projecting outwardly beyond said tubular member and beyond said bearingsupporting rings, and through and beyond said cylindrical openings in said second set of discs, said ends of said shaft having cylindrical sections of reduced diameter that are concentric with said center of said shaft and that coact with said center of said shaft to define radially-directed shoulders, said shoulders receiving and limiting movement of said second set of discs toward each other, said shaft having threaded sections disposed axially outwardly of said reduced diameter sections thereof, and nuts that telescope over said threaded sections and force said second set of discs against said shoulders, saidY shaft having a pulley-receiving portion disposed outwardly of the threaded portion at one end of said shaft, said projections on said bearing-supporting rings limiting movement of said side walls radially of said bearing-supporting rings and thereby minimizing the shearing forces on said fasteners.

4. A high speed vibrating device that comprises a frame with two spaced-apart side Walls, a tubular member that is disposed between said side walls of said frame, openings in said side walls of said frames that are in register With each other, the opposite ends of said tubular member extending through said openings, annular supporting members that are mounted on said opposite ends of said tubular member, said annular supporting members having radially extending flanges that are coextensive with portions of said side walls and having axially extending projections that engage said openings in said side 'walls of said frame, anti-friction bearings xedly held relative to said tubular member, said annular supporting members having the radially extending flanges thereof extending radially outwardly beyond the outer races of said anti-friction bearings, an elongated shaft that has the center thereof disposed 'within said tubular member and has the ends thereof projecting outwardly beyond said tubular member and beyond said annular supporting members, radially directed elements that are mounted on the opposite ends of said shaft and that extend to and are carried by the outer races of said antifriction bearings, and fasteners that hold said annular supporting members and said side walls of said frame in assembled relation, said projections on said annular 10 supporting members coaeting with those portions of said side walls of said frame that dene said openings to relieve said fasteners of shearing forces, said radially directed elements being adjustable to dispose said shaft eccentrically of said outer races of said anti-friction bearings.

References Cited in the le of this patent UNITED STATES PATENTS 1,931,657 Hetzel Oct. 24, 1933 2,066,362 Parks Jan. 5, 1937 2,246,483 Dillon June 17, 1941 2,267,143 Soldan Dec. 23, 1941 2,457,413 Stokes Dec. 28, 1948 2,677,967 Galbraith May 11, 1954 `2,778,231 Lamont De Gail Jan. 22, 1957 

